Carbon Chemist

Tag: biotech

  • WTF Is With the Pink Pineapples at the Grocery Store?!

    WTF Is With the Pink Pineapples at the Grocery Store?!

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    On a recent trip to Giant Eagle, my local grocery store in Pittsburgh, I noticed something new in the fruit section: a single pineapple packaged in a pink and forest-green box. A picture on the front showed the pineapple cut open, revealing rose-colored flesh. Touted as the “jewel of the jungle,” the fruit was the Pinkglow pineapple, a creation of American food giant Fresh Del Monte. It cost $9.99, a little more than double the price of a regular yellow pineapple.

    I put the box in my cart, snapped a picture with my phone, and shared the find with my foodie friends. I mentioned that its color is the result of genetic modification—the box included a “made possible through bioengineering” label—but that didn’t seem to faze anyone. When I brought my Pinkglow to a Super Bowl party, people oohed and aahed over the color and then gobbled it down. It was juicier and less tart than a regular pineapple, and there was another difference: It came with the characteristic crown chopped off. Soon enough, my friends were buying pink pineapples too. One used a Pinkglow to brew homemade tepache, a fermented drink made from pineapple peels that was invented in pre-Columbian Mexico.

    At a time when orange cauliflower and white strawberries are now common sights in American grocery stores, a non-yellow pineapple doesn’t seem all that out of place. Still, I wondered: Why now with the flashy presentation? And why pink? And why had my friends and I snapped it right up?

    When I brought my questions to Hans Sauter, Fresh Del Monte’s chief sustainability officer and senior vice president of R&D and agricultural services, he began by offering me a brief history of the fruit. You may assume, like I did, that pineapples have always been sweet and sunny-colored—but that wasn’t the case prior to the 1990s. Store-bought pineapples of yesteryear had a green shell with light yellow flesh that was often more tart than sweet. Buying a fresh one was a bit of a gamble. “Nobody could tell, really, whether the fruit was ripe or not, and consumption of pineapples was mostly canned product, because people could trust what they would eat there,” Sauter says. The added sugar in some canned pineapple made it a sweeter, more consistent product.

    In 1996 the company introduced the Del Monte Gold Extra Sweet, yellower and less acidic than anything on the market at the time. Pineapple sales soared, and consumers’ expectations of the fruit were forever changed. The popularity of the Gold led to an international pineapple feud when fruit rival Dole introduced its own varietal. Del Monte sued, alleging that Dole had essentially stolen its Gold formula. The two companies ended up settling out of court.

    With the success of its Gold pineapple, Del Monte was looking for new attributes that could make the pineapple even more enticing to consumers, Sauter says. But breeding pineapples is a slow process; it can take two years or longer for a single plant to produce mature fruit. Del Monte had spent 30 years crossbreeding pineapples with certain desired characteristics before it was ready to launch the Gold. Sauter says the possibility of waiting 30 more years for a new variety was “out of the question.” So in 2005 the company turned to genetic engineering.

    Del Monte didn’t set out to make a pink pineapple per se, but at the time, Sauter says, there was interest from consumers in antioxidant-rich fruits. (Acai bowls and pomegranate juice, anyone?) Pineapples happen to naturally convert a reddish-pink pigment called lycopene, which is high in antioxidants, into the yellow pigment beta-carotene. (Lycopene is what gives tomatoes and watermelon their color.) Preventing this process, then, could yield pink flesh and higher antioxidants. The company set its dedicated pineapple research team to the task of figuring out how to do it.

    The team landed on a set of three modifications to the pineapple genome. They inserted DNA from a tangerine to get it to express more lycopene. They added “silencing” RNA molecules to mute the pineapple’s own lycopene-converting enzymes, which also helped reduce its acidity. (RNA silencing is the same technique used to make non-browning GMO Arctic apples.) Finally, Del Monte added a gene from tobacco that confers resistance to certain herbicides, though representatives for the company say this was simply so its scientists could confirm that the other genetic changes had taken effect—not because Del Monte plans to use those herbicides in production.

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  • There’s New Hope for an HIV Vaccine

    There’s New Hope for an HIV Vaccine

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    Since it was first identified in 1983, HIV has infected more than 85 million people and caused some 40 million deaths worldwide.

    While medication known as pre-exposure prophylaxis, or PrEP, can significantly reduce the risk of getting HIV, it has to be taken every day to be effective. A vaccine to provide lasting protection has eluded researchers for decades. Now, there may finally be a viable strategy for making one.

    An experimental vaccine developed at Duke University triggered an elusive type of broadly neutralizing antibody in a small group of people enrolled in a 2019 clinical trial. The findings were published today in the scientific journal Cell.

    “This is one of the most pivotal studies in the HIV vaccine field to date,” says Glenda Gray, an HIV expert and the president and CEO of the South African Medical Research Council, who was not involved in the study.

    A few years ago, a team from Scripps Research and the International AIDS Vaccine Initiative (IAVI) showed that it was possible to stimulate the precursor cells needed to make these rare antibodies in people. The Duke study goes a step further to generate these antibodies, albeit at low levels.

    “This is a scientific feat and gives the field great hope that one can construct an HIV vaccine regimen that directs the immune response along a path that is required for protection,” Gray says.

    Vaccines work by training the immune system to recognize a virus or other pathogen. They introduce something that looks like the virus—a piece of it, for example, or a weakened version of it—and by doing so, spur the body’s B cells into producing protective antibodies against it. Those antibodies stick around so that when a person later encounters the real virus, the immune system remembers and is poised to attack.

    While researchers were able to produce Covid-19 vaccines in a matter of months, creating a vaccine against HIV has proven much more challenging. The problem is the unique nature of the virus. HIV mutates rapidly, meaning it can quickly outmaneuver immune defenses. It also integrates into the human genome within a few days of exposure, hiding out from the immune system.

    “Parts of the virus look like our own cells, and we don’t like to make antibodies against our own selves,” says Barton Haynes, director of the Duke Human Vaccine Institute and one of the authors on the paper.

    The particular antibodies that researchers are interested in are known as broadly neutralizing antibodies, which can recognize and block different versions of the virus. Because of HIV’s shape-shifting nature, there are two main types of HIV and each has several strains. An effective vaccine will need to target many of them.

    Some HIV-infected individuals generate broadly neutralizing antibodies, although it often takes years of living with HIV to do so, Haynes says. Even then, people don’t make enough of them to fight off the virus. These special antibodies are made by unusual B cells that are loaded with mutations they’ve acquired over time in reaction to the virus changing inside the body. “These are weird antibodies,” Haynes says. “The body doesn’t make them easily.”

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  • The First Person to Receive a Pig Kidney Transplant Has Died

    The First Person to Receive a Pig Kidney Transplant Has Died

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    Richard “Rick” Slayman, the first person to receive a kidney from a genetically modified pig, has died almost two months after the transplant. He was 62.

    The historic procedure was carried out on March 16 at Massachusetts General Hospital. In a statement released on May 11, the hospital said it had “no indication” that Slayman’s death was the result of the pig kidney transplant.

    Slayman had previously received a kidney from a human donor in 2018, but it began to fail in 2023. He was a candidate for another human kidney transplant, but because of a shortage of available organs, he would have likely waited years to receive one. Kidneys are the most needed of all donor organs, with nearly 90,000 people in the US alone waiting to receive one. For decades, researchers have been interested in the idea of using animal organs to address this problem.

    Slayman’s doctors suggested a pig kidney transplant after months of dialysis complications. In dialysis, a machine connects to a major blood vessel to remove waste and excess fluid when the kidneys have stopped functioning. But Slayman’s blood vessels kept clotting and failing, landing him in the hospital regularly and significantly impacting his quality of life.

    Pig kidney transplants had been tested only in recently deceased individuals up until then. Slayman was the first living person to receive one. “I saw it not only as a way to help me, but a way to provide hope for the thousands of people who need a transplant to survive,” Slayman said in a hospital statement in March.

    In a press conference on March 21, Slayman’s surgical team reported that the kidney had started working normally shortly after it was in place. About a week after the transplant, however, doctors noticed initial signs of rejection. They were able to treat Slayman quickly with drugs to counteract this, and afterward he was doing so well that he was released from the hospital. No further details are known about Slayman’s condition after his discharge. When contacted by WIRED, a spokesperson for Massachusetts General said the hospital could not provide any other information at this time.

    A second living person, 54-year-old Lisa Pisano, received a genetically engineered pig kidney last month. That surgery, which also included transplanting the pig’s thymus gland, was carried out at NYU Langone Health.

    Transplanting organs from one species to another is known as xenotransplantation. The primary hurdle with using pig organs in people is the human immune system, which recognizes animal tissue as foreign and rejects it.

    To address this incompatibility, scientists have turned to genetic engineering. In Slayman’s case, surgeons used a pig with 69 genetic edits, created by eGenesis, a biotech company in Cambridge, Massachusetts. The edits removed harmful pig genes and added certain human ones.

    In the New York case, Pisano received a kidney from a pig with a single genetic edit, produced by Revivicor in Virginia. Her doctors are instead relying on the implanting of the pig’s thymus, an organ that’s part of the immune system, to help prevent rejection. Patients that get pig transplants will also need to take immunosuppressant drugs for the rest of their lives to reduce the risk of rejection.

    In 2022 and 2023, surgeons at the University of Maryland tried transplanting hearts from gene-edited pigs into two patients who were not eligible for human ones. In those cases, pigs with 10 genetic edits were used. Both individuals died around two months after their transplants.

    In a statement released by Mass General, Slayman’s family said they feel comforted by the optimism he provided other patients who are waiting for a transplant. “His legacy will be one that inspires patients, researchers, and health care professionals everywhere,” they said.

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  • These Artificial Blood Platelets Could One Day Save Lives

    These Artificial Blood Platelets Could One Day Save Lives

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    When donated blood is in low supply, platelets are even scarcer. These cell fragments, which are essential for blood clotting, have a short shelf life. Whereas whole blood can be refrigerated for up to a month, platelets last for just a week at most.

    “Even if you have a ton of donations, you can’t bank them for long,” says Ashley Brown, an associate professor in the joint biomedical engineering program at North Carolina State University and the University of North Carolina at Chapel Hill.

    To address this problem, Brown and her team have created an artificial substitute that could be stored for long periods of time. In a recent paper in Science Translational Medicine, they describe using their synthetic platelets to stop bleeding and promote healing in rodents and pigs.

    Natural platelets circulate in the blood and prevent or stop bleeding by forming clots. Sometimes, the body needs more of them. People with traumatic injuries, cancer, and certain chronic conditions that strip the blood of platelets often require transfusions. Typically, platelets are collected through a process called apheresis, in which a donor’s blood is passed through a tube and into a machine that separates out the platelets. These are funneled into a bag, and the rest of the blood is returned to the donor.

    Their limited shelf life also means they’re not often stored in rural hospitals and can’t be easily transported. Brown’s aim is to make an alternative that’s easy to store and ship that could be given to patients sooner, such as in an ambulance or on the battlefield, and regardless of blood type.

    To make their synthetic platelets, Brown and her team used a squishy water-based gel called a hydrogel to form nanoparticles that mimic the size, mechanics, and shape of natural platelets. They then designed an antibody fragment that binds to fibrin, a protein that helps platelets form clots, and decorated the surface of the nanoparticles with this fibrin antibody. When an injury occurs, platelets rush to the site of damage to form a temporary plug. Fibrin also gets activated in this process and builds up at the wound site, eventually producing a clot.

    To find the optimal dose of artificial platelets needed to stop bleeding, researchers tested a range of doses in mice. They then gave infusions of the artificial version to mice, rats, and pigs and compared them to animals that received natural platelets and those that were not treated with either. All the animals in the study had severe internal bleeding. They found that the synthetic platelets were able to travel through the bloodstream to the wound site to promote clotting and accelerate healing.

    Healing rates were similar in animals that received synthetic platelets and those that received natural ones. Overall, both groups fared better than those in the untreated group. Interestingly, the researchers only had to use about a tenth as many artificial particles to get the same healing effects as with natural platelets. “Our mechanism of action is binding to fibrin, so it could just be that our particles are more efficient in that binding,” Brown says. There’s also variability in how labs prepare natural platelets that can affect their quality, which might have accentuated this difference.

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  • The US Is Cracking Down on Synthetic DNA

    The US Is Cracking Down on Synthetic DNA

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    The White House has issued new rules aimed at companies that manufacture synthetic DNA after years of warnings that a pathogen made with mail-order genetic material could accidentally or intentionally spark the next pandemic.

    The rules, released on April 29, are the result of an executive order signed by President Joe Biden last fall to establish new standards for AI safety and security, including AI applied to biotechnology.

    Artificially generated DNA allows researchers to do all sorts of things—develop diagnostic tests, make beneficial enzymes to eat up plastic, or engineer potent antibodies to treat disease—without having to extract natural sequences from organisms. Need to study a rare type of bacteria? Instead of going out into the field to collect a sample, its genetic sequence can simply be ordered from a DNA synthesis company instead.

    Synthesizing DNA has been possible for decades, but it’s become increasingly easier, cheaper, and faster to do so in recent years thanks to new technology that can “print” custom gene sequences. Now, dozens of companies around the world make and ship synthetic nucleic acids en masse. And with AI, it’s becoming possible to create entirely new sequences that don’t exist in nature—including those that could pose a threat to humans or other living things.

    “The concern has been for some time that as gene synthesis has gotten better and cheaper, and as more companies appear and more technologies streamline the synthesis of nucleic acids, that it is possible to de novo create organisms, particularly viruses,” says Tom Inglesby, an epidemiologist and director of the Johns Hopkins Center for Health Security.

    It’s conceivable that a bad actor could make a dangerous virus from scratch by ordering its genetic building blocks and assembling them into a whole pathogen. In 2017, Canadian researchers revealed they had reconstructed the extinct horsepox virus for $100,000 using mail-order DNA, raising the possibility that the same could be done for smallpox, a deadly disease that was eradicated in 1980.

    The new rules aim to prevent a similar scenario. It asks DNA manufacturers to screen purchase orders to flag so-called sequences of concern and assess customer legitimacy. Sequences of concern are those that contribute to an organism’s toxicity or ability to cause disease. For now, the rules only apply to scientists or companies that receive federal funding: They must order synthetic nucleic acids from providers that implement these practices.

    Inglesby says it’s still a “big step forward” since about three-quarters of the US customer base for synthetic DNA are federally funded entities. But it means that scientists or organizations with private sources of funding aren’t beholden to using companies with these screening procedures.

    Many DNA providers already follow screening guidelines issued by the Department of Health and Human Services in 2010. About 80 percent of the industry has joined the International Gene Synthesis Consortium, which pledges to vet orders. But these measures are both voluntary, and not all companies comply.

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  • China Has a Controversial Plan for Brain-Computer Interfaces

    China Has a Controversial Plan for Brain-Computer Interfaces

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    At a tech forum in Beijing last week, a Chinese company unveiled a “homegrown” brain-computer interface that allowed a monkey to seemingly control a robotic arm just by thinking about it.

    In a video shown at the event, a monkey with its hands restrained uses the interface to move a robotic arm and grasp a strawberry. The system, developed by NeuCyber NeuroTech and the Chinese Institute for Brain Research, involves soft electrode filaments implanted in the brain, according to state-run news media outlet Xinhua.

    Researchers in the US have tested similar systems in paralyzed people to allow them to control robotic arms, but the demonstration underscores China’s progress in developing its own brain-computer interface technology and vying with the West.

    Brain-computer interfaces, or BCIs, collect and analyze brain signals, often to allow direct control of an external device, such as a robotic arm, keyboard, or smartphone. In the US, a cadre of startups, including Elon Musk’s Neuralink, are aiming to commercialize the technology.

    William Hannas, lead analyst at Georgetown University’s Center for Security and Emerging Technology (CSET), says China is quickly catching up with the US in terms of its BCI technology. “They’re strongly motivated,” he says of the Asian superpower. “They’re doing state-of-the-art work, or at least as advanced as anybody else in the world.”

    He says China has typically lagged behind the US in invasive BCIs—that is, those that are implanted in the brain or on its surface—choosing instead to focus on noninvasive technology that’s worn on the head. But it’s quickly catching up on implantable interfaces, which are being explored for medical applications.

    More concerning, though, is China’s interest in noninvasive BCIs for the general population. Hannas coauthored a report released in March that examines Chinese research on BCIs for nonmedical purposes.

    “China is not the least bit shy about this,” he says, referring to ethical guidelines released by the Communist Party in February 2024 that include cognitive enhancement of healthy people as a goal of Chinese BCI research. A translation of the guidelines by CSET says, “Nonmedical purposes such as attention modulation, sleep regulation, memory regulation, and exoskeletons for augmentative BCI technologies should be explored and developed to a certain extent, provided there is strict regulation and clear benefit.”

    The translated Chinese guidelines go on to say that BCI technology should avoid replacing or weakening human decisionmaking capabilities “before it is proven to surpass human levels and gains societal consensus, and avoid research that significantly interferes with or blurs human autonomy and self-awareness.”

    These nonmedical applications refer to wearable BCIs that rely on electrodes placed on the scalp, also known as electroencephalography or EEG devices. Electrical signals from the scalp are much harder to interpret than those inside the brain, however, and there’s a huge effort in China to use machine learning techniques to improve analysis of brain signals, according to the CSET report.

    A handful of US companies are also developing wearable BCIs that arguably fall under the category of cognitive enhancement. For instance, Emotiv of San Francisco and Neurable in Boston are starting to sell EEG headsets intended to improve attention and focus. The US Department of Defense has also funded research on wearable interfaces that could ultimately enable control of cyber-defense systems or drones by military personnel.

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  • Doctors Combined a Heart Pump and Pig Kidney Transplant in Breakthrough Surgery

    Doctors Combined a Heart Pump and Pig Kidney Transplant in Breakthrough Surgery

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    A 54-year-old New Jersey woman has become the second living person to receive a genetically engineered pig kidney. The surgery, carried out at NYU Langone Health on April 12, also involved transplanting the pig’s thymus gland to help prevent rejection.

    The patient, Lisa Pisano, had a mechanical heart pump implanted days before getting the transplant. She was facing heart failure and end-stage kidney disease and wasn’t eligible for a human organ transplant because of several other medical conditions. Her medical team says she’s recovering well.

    “I feel fantastic,” Pisano said from her hospital bed over Zoom during a press conference on Wednesday. “When this opportunity came, I said, ‘I’m gonna take advantage of it.’”

    It’s the first instance of a patient with a mechanical heart pump receiving an organ transplant of any kind. It is the second known transplant of a gene-edited pig kidney into a living person, and the first with the pig’s thymus combined.

    The series of procedures was performed over a span of nine days. In the first, surgeons implanted the heart pump, a device called a left ventricular assist device, to replace the function of her failing heart. It’s used in patients who are awaiting heart transplantation or otherwise aren’t a candidate for a heart transplant. Without it, Pisano’s life expectancy would have been just days or weeks.

    Close up of surgeon working on organ transplant

    PHOTOGRAPH: JOE CARROTTA FOR NYU LANGONE HEALTH

    The second surgery involved transplanting the pig organs. The animal’s thymus gland, which is responsible for educating the immune system, was placed under the covering of the kidney. The addition of the pig thymus is meant to reprogram Pisano’s immune system to be less likely to reject the kidney and hopefully allow doctors to reduce the amount of immunosuppressive drugs she has to take, said Robert Montgomery, director of NYU Langone’s Transplant Institute, during the press conference.

    It’s the latest attempt to transplant an animal organ in a person—a process known as xenotransplantation—as a potential way to address the organ shortage and offer transplants to people who otherwise wouldn’t get them. In the US alone, there are more than 100,000 people on the national transplant waiting list, and every day 17 people die waiting for an organ. Strict eligibility criteria means that organs are prioritized for relatively healthy patients, leaving patients like Pisano with few other options.

    Starting in 2021, the NYU team began experimenting with transplanting genetically engineered pig hearts and kidneys into deceased humans following brain death. With the consent of their families, the patients were kept on a ventilator so that researchers could assess the viability of the pig organs. In one instance, a pig kidney was able to function in a human body for up to two months—a record for xenotransplantation. In monkeys, pig kidneys have been shown to work for up to two years. Now, scientists are testing whether they can support humans in need of new kidneys.

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  • The Next Frontier for Brain Implants Is Artificial Vision

    The Next Frontier for Brain Implants Is Artificial Vision

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    Brian Bussard has 25 tiny chips in his brain. They were installed in February 2022 as part of a study testing a wireless device designed to produce rudimentary vision in blind people. Bussard is the first participant.

    Bussard, who’s 56, lost vision in his left eye at age 17 after his retina detached. The right eye followed in 2016, leaving him completely blind. He remembers the exact moment it happened. “It was the hardest thing I’ve ever gone through,” he says. Eventually, he learned to adapt.

    In 2021, he heard about a trial of a visual prosthesis at Illinois Institute of Technology in Chicago. Researchers cautioned that the device was experimental and he shouldn’t expect to regain the level of vision he had before. Still, he was intrigued enough to sign up. Thanks to the chips in his brain, Bussard now has very limited artificial vision—what he describes as “blips on a radar screen.” With the implant, he can perceive people and objects represented in white and iridescent dots.

    Bussard is one of a small number of blind individuals around the world who have risked brain surgery to get a visual prosthesis. In Spain, researchers at Miguel Hernández University have implanted four people with a similar system. The trials are the culmination of decades of research.

    There’s interest from industry, too. California-based Cortigent is developing the Orion, which has been implanted in six volunteers. Elon Musk’s Neuralink is also working on a brain implant for vision. In an X post in March, Musk said Neuralink’s device, called Blindsight, is “already working in monkeys.” He added: “Resolution will be low at first, like early Nintendo graphics, but ultimately may exceed normal human vision.”

    That last prediction is unlikely, considering vision is such a complex process. There are huge technical barriers to improving the quality of what people are able to see with a brain implant. Yet even generating rudimentary sight could provide blind individuals with greater independence in their everyday lives.

    “This is not about getting biological vision back,” says Philip Troyk, a professor of biomedical engineering at Illinois Tech, who’s leading the study Bussard is in. “This is about exploring what artificial vision could be.”

    When light hits the eye, it first passes through the cornea and the lens, the outer and middle layers of the eye. When light reaches the back of the eye—the retina—cells there called photoreceptors convert it into electrical signals. These electrical signals travel through the optic nerve to the brain, which interprets those signals as the images we see.

    Without an intact retina or optic nerve, the eyes can’t communicate with the brain. This is the case for many people with total blindness. The types of devices that Troyk and Neuralink are building bypass the eye and optic nerve completely, sending information straight to the brain. Because of this, they have the potential to address any cause of blindness, whether due to eye disease or trauma.

    The specific brain region that processes information received from the eyes is called the visual cortex. Its location at the back of the head makes it easily accessible for an implant. To place the 25 chips in Bussard’s brain, surgeons performed a routine craniotomy to remove a piece of his skull.



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  • He Got a Pig Kidney Transplant. Now Doctors Need to Keep It Working

    He Got a Pig Kidney Transplant. Now Doctors Need to Keep It Working

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    Other than rejection of the organ, one of the most common transplant complications is infection. Doctors have to strike a balance when prescribing immunosuppressive drugs: too low a dose can lead to rejection, while too much can make a patient vulnerable to infection. Immunosuppressants are powerful drugs that can cause a range of side effects, including fatigue, nausea, and vomiting.

    Despite the deaths of the two pig heart recipients, Riella is optimistic about Slayman’s transplant. For one, he says, Slayman was relatively healthy when he underwent the surgery. He qualified for a human kidney but because of his rare blood type he would likely need to wait six to seven years to get one. The two individuals who received pig heart transplants were so ill that they didn’t qualify for a human organ.

    In addition to close monitoring and traditional immunosuppressants, Slayman’s medical team is treating him with an experimental drug called tegoprubart, developed by Eledon Pharmaceuticals of Irvine, California. Given every three weeks via an IV, tegoprubart blocks crosstalk between two key immune cells in the body, T cells and B cells, which helps suppress the immune response against the donor organ. The drug has been used in monkeys that have received gene-edited pig organs.

    Hospital patient

    Photograph: Massachusetts General Hospital

    “It’s pretty miraculous this man’s out of the hospital a couple of weeks after putting in a pig kidney,” says Steven Perrin, Eledon’s president and chief scientific officer. “I didn’t think we would be here as quickly as we are.”

    Riella is also hopeful that the 69 genetic alterations made to the pig that supplied the donor organ will help Slayman’s kidney keep functioning. Pig organs aren’t naturally compatible in the human body. The company that supplied the pig, eGenesis, used Crispr to add certain human genes, remove some pig genes, and inactivate latent viruses in the pig genome that could hypothetically infect a human recipient. The pigs are produced using cloning; scientists make the edits to a single pig cell and use that cell to form an embryo. The embryos are cloned and transferred to the womb of a female pig so that her offspring end up with the edits.

    “We hope that this combination will be the secret sauce to getting this kidney to a longer graft survival,” Riella says.

    There’s debate among scientists over how many edits pig organs need to last in people. In the pig heart transplants, researchers used donor animals with 10 edits developed by United Therapeutics subsidiary Revivicor.

    There’s another big difference between this procedure and the heart surgeries: If Slayman’s kidney did stop working, Riella says, he could resume dialysis. The pig heart recipients had no back-up options. He says even if pig organs aren’t a long-term alternative, they could provide a bridge to transplant for patients like Slayman who would otherwise spend years suffering on dialysis.

    “We’ve gotten so many letters, emails, and messages from people volunteering to be candidates for the xenotransplants, even with all the unknowns,” Riella says. “Many of them are struggling so much on dialysis that they’re looking for an alternative.”

    The Mass General team plans to launch a formal clinical trial to transplant edited pig kidneys in more patients. They received special approval from the US Food and Drug Administration for just one procedure. For now, though, their main focus is on keeping Slayman healthy.

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  • This Bag of Cells Could Grow New Livers Inside of People

    This Bag of Cells Could Grow New Livers Inside of People

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    In early experiments, Lagasse found that if he injected healthy liver cells into the lymph nodes of mice, the cells would flourish and form a second, smaller liver to take over the functions of the animal’s failing one. The new livers grew up to 70 percent of the size of a native liver. “What happened is that the liver grew to a certain size and then stopped growing when it reached the level necessary for normal function,” Lagasse says.

    At the University of Pittsburgh, Lagasse and his colleagues also tested the approach in pigs. In a study published in 2020, they found that pigs regained liver function after getting an injection of liver cells into an abdominal lymph node. When the scientists examined the lymph nodes with miniature livers, they found that a network of blood vessels and bile ducts had spontaneously formed. The more severe the damage in the pigs’ native liver, the bigger the second livers grew, suggesting the animals’ bodies may be able to recognize the healthy liver tissue and transfer responsibilities to it.

    “It is remarkable to identify lymph nodes as a reproducible and fertile bed for the regeneration of a variety of tissues and organs in two different animal species,” Abla Creasey, vice president of therapeutics development at the California Institute for Regenerative Medicine, says of the company’s approach. “These findings suggest that such an approach could present an alternative tissue source for patients with failing organs,”

    Elliot Tapper, a liver specialist at the University of Michigan, is also excited by the prospect of turning a lymph node into a new liver. “Even though it’s not where the liver was intended to sit, it can still do some liver functions,” he says.

    The most likely benefit of the LyGenesis treatment, he says, would be removing ammonia from the blood. In end-stage liver disease, ammonia can build up and travel to the brain, where it causes confusion, mood swings, falls, and sometimes comas. He doesn’t think the new mini organs could do all the jobs of a natural liver though, because they contain cell types other than hepatocytes.

    One of the big questions is how many cells it will require for humans to grow a liver big enough to take over certain vital functions, such as filtering blood and producing bile. In the LyGenesis trial, three additional patients will get an injection of 50 million cells into a single lymph node—the lowest “dose.” If that seems safe, a second group of four will get 150 million cells into three different lymph nodes. A third group would get 250 million cells in five lymph nodes—meaning they could have five mini livers growing inside them.

    The effects of the therapy won’t be immediate. Hufford says it will likely take two to three months for the new organ to grow big enough to take over some of the functions of the native liver. And like organ donor recipients, trial participants will need to go on immunosuppressant drugs for the rest of their lives to prevent their body from rejecting the donor cells.

    If the approach works, it could provide a life-saving alternative to liver transplantation for some patients. “If they prove it’s effective and safe,” Tapper says, “there will definitely be candidates that are interested in this kind of intervention.”

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